1. Preparation work
(1) Installation of winch:
1) The distance between the winch and the pile hole should be controlled to be around 15 meters, and should not be too far away. It should not be too far away. If the distance is too big, the wire rope swings too much when impacting, the impact energy loss is big and unsafe. At the same time affect the line of sight, can not see, it is not easy to control the height of the hammer, especially at night, it is easy to hit the empty hammer accident.
②The winch drum should be aligned with the pulley groove, to prevent the wire rope out of the groove strangulation, resulting in danger.
③A ground anchor shall be set behind the winch to connect with the winch and pull the winch to stop forward movement.
(2) impact system connection:
①Steering ring and hammer head connection: the prepared connecting ring (diameter of 50 mm round steel, made of about 110 ~ 120 cm long) through the lower end of the steering ring, and then the connecting ring's two legs and hammer head welded firmly. The length of the weld is not less than 30 centimeters.
② winch and hammer connection: one end of the main pulling wire rope is fixed on the winch, the other end through the ground pulley, top pulley, and the upper end of the steering ring connection, in order to increase the wire rope in the bending part of the force radius, extend the service life of the wire rope, the wire rope in the bending part of the installation of special groove iron guard. Fixed wire rope of the first buckle can not be screwed too tightly, in order to avoid the wire rope after the force here injured and break off. Generally use 3 snaps, the spacing between the snaps should be not less than 6 times the diameter of the wire rope.
(3) burying the barrel guard:
① digging pit: digging depth 0.5 ~ 1 meter. The mouth of the barrel must be at least 50 centimeters above the ground to keep the water level inside the hole higher than the water level outside the hole or the ground, so that the water pressure inside the hole increases, which is conducive to the protection of the hole wall does not collapse. After the pit is dug, the bucket is placed.
② backfill: first in the periphery of the barrel bottom pad about 20 cm thick cement (rake mud) with a foot tight, and then stacked loess straw bags, straw bags staggered stacked, laid a layer of straw bags, and then lay a layer of cement, step on the tight after stacking the second layer of straw bags, and then lay a layer of cement, step on the tight, and so on, so that more successive fillings, so that it is slightly below the mouth of the barrel of the barrel of the guard about 20 cm so far. Loess grass bags and mud must be layers of dense, so that both prevent the river water infiltration, while making the barrel fixed.
3 Preparation of the wall material: if the surface for the soft soil, in the protection of the barrel with flakes, gravel and loess, the ratio of roughly 3:1:1. such as the surface for the gravel and pebbles, in the protection of the barrel with only small stones (small particles of gravel) and loess, the ratio of roughly 1:1. all these work should be done before the beginning of the punching hole.
2. Hole
(1) opening: in the opening stage of the hole punching progress should not be too fast, the general console class footage within 1 meter, accordingly, the height of the hammer should be small, the impact of the number of times to be more (see table below), so that the impact force is small, so that the hole wall is gradually by the horizontal force of the extrusion and densification.
Soil lifting hammer height (cm) impact times (times/minute) slurry concentration
Soil 40 ~ 6020 ~ 251.4 ~ 1.5
Sand gravel 40 ~ 6020 ~ 251.5 ~ 1.7
At this time, if the impact is too strong, progress too fast, the hole wall can not be formed better, but will cause the collapse of the hole. Therefore, the progress of punching should be strictly controlled in the opening stage to help strengthen the hole wall. In the depth of the opening hole, the bottom of the barrel below 3 to 4 meters, the requirements of the hole wall as far as possible to protect some solid, and thereafter into the normal punching, it is not easy to produce slump holes.
(2) normal punching: after the light impact of the opening stage, that is, start normal punching to speed up. Lift the hammer height can be increased to 1.5 ~ 2 meters or more, the mud concentration is reduced accordingly, roughly below 1.5. Under normal circumstances, the punching footage per shift is about 1 to 1.5 meters, sometimes a little more.
(3) Punching rock layer: the surface of the rock layer is mostly uneven, or inclined surface, so when punching just into the rock layer,
it is most likely to produce biased holes. So when punching the hole to contact the rock layer, be especially careful. Usually is to the bottom of the hole throwing 20 ~ 30 cm in diameter flake, the rock layer slope and unevenness of the embedded fill. Then the taut rope low-hammer fast hitting, resulting in a tighter platform to support the punch hammer, uniform force, to prevent deviation of the hole. However, it should be noted that before the tilted protruding part of the rock layer is not flattened, still can not raise the hammer, to be basically flattened rock layer, before the high hammer to accelerate the progress of punching.
After punching into the rock layer, the mud concentration is reduced to about 1.2 to reduce the resistance and sticking to the hammer, but not too small, otherwise the rock slag can't float up, and it is difficult to pull out the slag.
3. slagging
In the process of punching the stone slag, part of the mud and mud into the hole wall void, most of the slag by the cylinder to remove out. In the opening stage, in order to make the stone slag slurry folder stone as much as possible squeezed into the hole wall around the pore space, in order to solid hole wall, so in the process of the impact does not pull out the stone slag, to be flushed into the 4 ~ 5 meters, after a slagging to reduce the concentration of slurry. In the normal punching stage, slagging should be timely, otherwise the resistance is too large, not conducive to impact. Generally every shift slagging once, each time out of stone slag slurry 4 to 5 barrels, but in the slagging at the same time to pay attention to two points:
(1) timely addition of water to the hole, to maintain the water level in the hole must be high, so as to avoid the collapse of the hole by reducing the water pressure.
(2) after hollowing out the stone slag, should be immediately added to the hole wall material, restore the normal concentration of mud. Such a cycle of replacement, can ensure the smooth progress of punching. As for punching into the rock layer later, generally also every shift to pull out slag once, each time to pull out the slurry 5 to 6 barrels.
4. Under the steel cage
For the convenience of lifting and placing the steel cage, the cage should not be too long, each section of 8 to 10 meters, so the length of the cage can be based on the depth of the pile hole and its total length in sections tied, and in order to increase the rigidity of lifting the steel cage, you can take a temporary measure, with a diameter of about 15 centimeters of the round logs, half of the length of the steel cage, tied in the middle of the cage, the cage. After the cage is erected, the log will be lifted and then lowered.
According to the height of the tripod and the length of the cage to take the following method of lifting:
Reinforcement cages are lifted in sections, but in the upper end of the tripod to set up a one-legged picket to increase the height of the lifting, the first section of the cage lifting hole, and hang it, that is, the second section of the cage up, to the first section, welded, welding, welding, withdrawal of the facilities of the cage, and then continue to be lifted. Hanging down.
When lifting and lowering the cage, control the speed of lifting and lowering. Lifting should be slow, the speed should be even, so that the cage along the tripod foot slowly rise, gradually erected. Lifting too violently, may make the cage deformation, after the cage lifting vertical, to make it straight and slowly down, to prevent the cage swinging in the hole. Collision with the hole wall, causing collapse.
5. Clearing
After the cage is placed, the hole will be cleared.
(1) Installation of hole-cleaning device:
In the vicinity of the mouth of the hole, the hole-cleaning conduit is put together in two sections, and put together into several large sections. The lower section is connected to the intake pipe, and the upper section is installed with the nozzle elbow. Then use the top pulley of the hanger to lift and lower in sequence. First of all, the bottom of a large section into the hole, down to the appropriate position to hang on, then the second section of the hang up and link, so more successive lifting down, until the whole conduit installation is completed. Conduit to be 3 to 4 meters above the ground, the nozzle should be aligned with the outlet, in order to prevent the conduit from turning out of the accident, with two logs will be clamped to the conduit, that is, to control the direction of the spray, but also to play a role in holding down the conduit. At the same time to connect the water source. After the start of clearing the hole, that is, to the hole water, in order to maintain the water level in the hole, to avoid causing the collapse of the hole.
(2) Clearing:
Air compressor and pumping machine start at the same time. The air pressure of the air compressor is not less than 6-7 kilograms. In accordance with the general principle of sand blower, the air compressor constantly to the conduit high-pressure gas, the conduit to form a generally strong high-pressure airflow upward run, be stirred mud with the high-pressure airflow upward, from the nozzle out (as follows), until the hole out of the clear water until. This is generally smaller than the diameter of the clearing tube pebbles can be removed, stay at the bottom of the hole is only individual larger than the diameter of the clearing tube pebbles, which is no harm to the quality of concrete.
Based on practical experience, it is believed that this method of clearing holes, basically can meet the requirements.
6. Filling of underwater concrete
(1) Installation of conduit:
1) At the same time as clearing the hole, that is, the preparation of filling concrete, and requires that before the completion of clearing the hole ready. After clearing the hole, remove the clearing equipment, lifting out the clearing device, then lifting the concrete conduit. Concrete conduit must be tested beforehand, and divided into several segments, in order to set up for lifting. Requirements for the conduit: it must be straight, no bending uneven, so as not to hinder the water ball drop; conduit connecting flange bolts should be tightened, do not leakage of water and slurry.
②Concrete conduit using three-legged hanger lifting and placing.
3 conduit should be placed in the center of the pile hole, to be fixed. The lower exit is 30-40 centimeters from the bottom of the hole, not too big. The diameter of the conduit used here is 30 centimeters, and the concrete spacer ball size is also larger, so the conduit exit from the bottom of the hole is larger, so the initial outflow of concrete occurs heavier washing. Conduit diameter of 20 or 25 centimeters is appropriate, the size of the water balloon should also be reduced, so that the conduit mouth from the bottom of the hole can be controlled within 30 to 35 centimeters, when the concrete washing phenomenon can be reduced. The top of the conduit is 3 to 4 meters above the ground or water surface, the water ball suspended below the water surface.
(2) filling concrete:
①concrete fluidity should not be too large, its slump is generally controlled in 18 ~ 20 cm or so.
② before cutting the ball must reserve enough concrete, the calculation must make the concrete buried conduit 50, 60 centimeters deep. After cutting the ball, the concrete must be continuously into the funnel, do not make the conduit concrete interruption.
3 control the depth of the conduit buried in the concrete, generally when the lower part of the conduit is buried in the concrete 2 ~ 2.5 meters, it is necessary to raise the tube, raise the tube must be careful to prevent outside the concrete, make sure that the lower end of the conduit is still buried in the concrete 100 cm or so, so as not to turn over the slurry out of the accident. If buried too deep, the tube will be difficult.
④The concrete is finished, the bucket will be removed.
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